Safety device

ABSTRACT

A safety device ( 23 ) for a fluid hose ( 14 ) having at one end one part ( 19 ) of a separable connector ( 18 ) by means of which the hose ( 14 ) may be connected to another pipe ( 21 ) carrying the other part ( 20 ) of the connector, the connector parts separating when the connector ( 18 ) is subjected to a tensile load. The device ( 23 ) includes an elongate tether ( 24 ) having one end attached to the hose ( 14 ) at or adjacent the one connector part ( 19 ) and its other end attached to the pipe ( 21 ) at or adjacent the other connector part ( 20 ). The tether ( 24 ) is arranged to break when the connector parts has exceeded a pre-set distance, the breaking strain of the tether ( 24 ) being lower than the load required to separate the connector ( 18 ).

[0001] This invention relates to a safety device for a fluid hose havingat one end a separable connector.

[0002] The safety device of the present invention is particularlyapplicable to liquid fuel dispensing hoses, as used for example ongarage forecourt fuel pumps. However, the invention may be used in otherareas of industry where a flexible hose is used to dispense a liquid orgas to a movable item, such as a vehicle, a container, or the like.Thus, though in the following the invention will primarily be describedwith reference to its use for forecourt fuel pumps, nevertheless it isto be understood that the invention is not limited to that use.

[0003] A recognised problem with a garage forecourt fuel pump having aflexible hose fitted at its free end with a dispensing nozzleincorporating a control valve is that the hose can become damaged, soleading to a loss of fuel which is both a fire risk and an environmentalhazard. One fairly common source of such hose damage is when a motorist,on completing the filling of his vehicle's fuel tank, then drives offleaving the dispensing nozzle still in the filler pipe of the vehicle. Asimilar problem can arise with L.P.G. where the nozzle is physicallyconnected to a vehicle's filler pipe.

[0004] In an attempt to minimise the damage to both the hose and thepump, and also to minimise the loss of fuel, it is known to fit aforecourt fuel pump hose with a two-part connector which automaticallyseparates when the hose is subjected to a tensile load above somepre-determined level. The two parts of the connector both includespring-loaded non-return valves which automatically close on theconnector separating under an applied tensile load, so as to prevent anyloss of fuel from the fuel pump side, bearing in mind that the pumpmight still be running, as well as from the part of the hose downstreamof the connector. Such connectors may be provided between a rigid pipeassociated with the fuel pump and the flexible hose, partway along thelength of the hose, or at the dispensing nozzle, to connect the hose tothe nozzle.

[0005] Though a two-part connector of the kind described above cansignificantly reduce the fire risk and pollution risk caused by amotorist driving away whilst the dispensing nozzle is still located inthe fuel filler pipe of his vehicle, it is found that if the connectoris to stay connected for all normal usage of the fuel pump, the tensileload required to separate the connector under emergency conditions mustbe set relatively high. In that case, considerable energy will be storedin the flexible hose by the tensile load applied to that hose at thepoint at which the connector parts separate. This stored energy, onbeing released on separation of the connector parts, can do considerabledamage to the fuel pump or the vehicle, depending upon the location ofthe connector. For example, if the connector is at the upstream end ofthe flexible hose, to connect that hose to a rigid pipe of the fuelpump, then the upstream end of the hose together with its connector partcan snake back to the vehicle, and cause significant damage to thevehicle. Conversely, if the connector is at the dispensing nozzle end,the free end of the hose can spring back towards the pump and causedamage there. Further, in either case, persons standing nearby can behit by the hose, moments after the connector separates.

[0006] The present invention aims to reduce the likelihood of damage toequipment in the vicinity of a flexible hose used to dispense liquids orgases, or injury to persons in the vicinity, in the event that the hoseis subjected to a sufficient tensile load to cause a connector providedin that hose to separate under the load.

[0007] According to one aspect of the present invention, there isprovided a safety device for a fluid hose having at one end one part ofa separable connector by means of which the hose may be freed fromanother pipe carrying the other part of the connector when the connectoris subjected to a tensile loads, which device comprises an elongatetether having one end attached to the hose at or adjacent said one partof the connector and its other end attached to the pipe at or adjacentthe other part of the connector, the tether being arranged to part whenthe connector parts have separated under an applied load only once theseparation of the connector parts exceeds a pre-set distance.

[0008] With the safety device of this invention, it will be appreciatedthat the likelihood of damage is reduced in the case of a hose having atwo-part connector separable by means of an applied tensile load, inview of the relatively low strength of the tether as compared to thetensile load required to separate the connector pads. The tether mayserve to absorb much of the energy stored in the hose at the point ofseparation, before the tether itself separates consequent upon theabsorption of that load or on being subjected to a continuing load.Then, the end of the hose having said one part of the connector maysimply fall to the ground, minimising the probability of any damage orinjury occurring.

[0009] It is highly preferred that the length of the tether is greaterthan the distance between the attachment points thereof, respectively tothe hose and the pipe. In this case, the excess length of the tether maybe contained in packaging disposed alongside the connector. For example,the packaging may comprise a rigid tube, the two end portions of thetether leaving the tube respectively through the two ends of the tube.To resist movement of the tether out of the tube, each end of the tubemay be provided with friction means engaging with the tether. In oneembodiment, such friction means comprises a resilient gland throughwhich the tether passes.

[0010] An alternative to having a tether of a greater length than thedistance between the attachment points thereof, the tether may comprisea strop of a synthetic polymer of a known kind, which undergoessignificant extension under a substantially constant tensile load untilthe strop has stretched to such a length that it has reached itsbreaking point. Such polymers are well known and include certain classesof polyethylene.

[0011] One end portion of the tether may be secured to the hose by meansof a loop formed from the tether to pass around the hose, which loop issecured to the hose by means of a ferrule crimped around the bight ofthe tether and the free end thereof. Of course, the other end of thetether may equally be secured to the pipe to which the hose is connectedin much the same way. In a case where the excess length of the tether iscontained in a tube, that tube may be secured to the connector, forexample by means of conventional plastic cable ties. As an alternative,the tether may be secured to the two parts of the coupling so as to beindirectly connected to the hose and pipe. In this case, each couplingpart may be provided with a lug to which the respective end portion ofthe tether is secured. A further possibility is to secure the tether tothe hose and pipe with plastic cable-ties which are easy to fit but canbe removed only by destroying the tie.

[0012] Yet another possibility is for the tether to be arranged toextend internally of the coupling itself, so as not to be visible oraccessible from the outside. Such a tether may operate in much the samemanner as has been described above. This arrangement would beparticularly suitable to a tether in the form of a strop which undergoessignificant elongation under a substantially constant tensile load,until breaking at some pre-defined extension.

[0013] It will be appreciated that the pipe carrying the other part ofthe connector could be a rigid pipe in the case of a forecourt fuelpump, with the connector mounted at the upstream end of the hose. In thealternative, the pipe could be the inlet duct of a dispensing nozzle,when the connector is mounted at the downstream end of the hose. For ahose having the connector provided partway between the ends, said pipewill be the other part of the flexible hose.

[0014] This invention relates to a liquid fuel pump having a flexiblefuel delivery hose connected to a fuel delivery pipe by means of atwo-part connector arranged to separate when the tensile load applied tothe hose exceeds a pre-determined value, whenever the connector isfitted with a safety device of this invention as described above. Saidpipe may comprise a further length of flexible hose, or a rigid pipe. Inthe alternative, the invention extends to a liquid fuel pump having aflexible fuel delivery hose connected to a dispensing nozzle by means ofa two-part connector arranged to separate when the tensile load appliedto the hose exceeds a pre-determined value, whenever the connector isfitted with a safety device of this invention as described above.

[0015] By way of example only, one specific embodiment of this inventionwill now be described in detail, reference being made to theaccompanying drawings, in which:-

[0016]FIGS. 1 and 2 diagrammatically illustrate the problem associatedwith a conventional forecourt fuel delivery flexible hose;

[0017]FIGS. 3, 4 and 5 illustrate the embodiment of a safety device asapplied to the system of FIGS. 1 and 2;

[0018]FIGS. 6, 7 and 8 illustrate an alternative arrangement using theembodiment of safety device, with a connector arranged adjacent thedelivery nozzle of a fuel pump;

[0019]FIGS. 9A, 9B and 9C illustrate the embodiment of safety device ofthis invention in greater detail; and

[0020]FIG. 10 is a diagrammatic cross-section through the device ofFIGS. 9A, 9B and 9C.

[0021] Referring initially to FIGS. 1 and 2, there is showndiagrammatically a vehicle 10 having a fuel filler pipe 11, in which hasbeen inserted the dispensing nozzle 12 of a conventional garageforecourt fuel pump 13. The nozzle 12 is connected to the fuel pump bymeans of a flexible hose 14 of a reinforced fuel-proof elastomericmaterial. The hose is secured to pump output rigid pipe 16 by means of ascrew-threaded connector 17 and has, near the rigid pipe 16, an in-lineseparable connector 18 having a first part 19 connected to the mainlength of the hose 14 and a second part 20 connected to a short length21 of the hose, between the connector 18 and the rigid pipe 16. Theconnector 18 is of a known design and is arranged to have its two parts19,20 separate automatically when the hose 14 is subjected to a tensileload exceeding some pre-determined value. The two connector parts 19,20are each provided with a respective automatically operating shut-offvalve, such that in the event the parts of the connector 18 separate,the valves close and the loss of fuel is minimised.

[0022] As shown in FIG. 2, the problem associated with the knownarrangement of FIG. 1 is that when the connector 18 separates on accountof the applied tensile load exceeding the predetermined value, forexample should the vehicle move off while the nozzle 12 is still locatedin the filler pipe 11, very considerable energy is stored in thestretched hose 14. On the parts of the connector 18 separating, the endof the hose 14 carrying the connector first part 19 springs back to thevehicle 10 and can cause significant damage, as shown diagrammaticallyat 22. In the alternative, or possibly in addition, the hose 14 onsnaking back towards the vehicle may cause injury to persons standing inthe vicinity of the pump 13.

[0023] FIGS. 3 to 5 show the arrangement of FIG. 1, but with a safetydevice of this invention associated with the connector 18. This safetydevice 23 includes a tether 24 having one end secured to hose 14immediately adjacent the first part 19 of connector 18, and the otherend of the tether secured to the short length of hose 21 connected tothe rigid pipe 16, again immediately adjacent the second part 20 ofconnector 18. The tether 24 has a greater length than the distancebetween its connection points and the excess length is hanked inside atube 25, as will be described in greater detail below.

[0024] On the vehicle 10 driving away and so imparting a sufficienttensile load to hose 14 to cause connector 18 to separate, the tetherwill pull out of the tube 25 and then absorb much of the energy of thehose 14, as shown in FIG. 4. If the vehicle immediately stops, onhearing the connector 18 separate, it is possible that the tether 24will be able to absorb all of the energy and so still keep the connectorparts linked together. On the other hand, if the vehicle continues tomove away, the tether itself will part, but since the tensile loadrequired to achieve this is very much less than that required toseparate the connector 18, little energy will be stored in the hose.Thus, the end of the hose 14 carrying first connector part 19 will fallharmlessly to the ground, as shown in FIG. 5.

[0025]FIGS. 6, 7 and 8 show an arrangement broadly similar to that ofFIGS. 3, 4 and 5 respectively, but here the connector 18 is providedbetween the downstream end of hose 14 and the dispensing nozzle 12. Inthis case, the safety device 23 is connected between the hose 14 and thetrigger guard 27 of the nozzle 12, with the tube 25 again lyingalongside the connector 18. In the event that the vehicle moves awaywith the nozzle 12 still in the filler pipe 11, the connector willseparate but the tether 24 will absorb much of the energy stored in hose14 (FIG. 7), before the tether separates as shown in FIG. 8 if thevehicle has not, by then, stopped. Again, the free end of the hose 14will fall harmlessly to the ground.

[0026]FIGS. 9A, 9B and 9C show in more detail the connector arrangement,as shown in FIG. 3. Hose 14 is provided with a crimped-on end fittinghaving a tube (not shown) extending within the end portion of hose 14,and a sleeve 30 crimped externally on to the hose. The tube has aprojecting external screw-thread; the first part 19 of the connector isthreaded thereon and is secured by lock nut 31. The arrangement of thesecond part 21 of connector 18 is essentially the same. The safetydevice 23 has the two ends of the tether 24 secured around the crimpedsleeves 30, such that the tube 25 of the safety device lies closelyalongside the two connector parts 19,20. If required, the tube may beheld in place by means of plastic cable ties.

[0027] On the connector 18 separating following an applied tensile loadto hose 14, the tether pays out of the tube 25 as shown in FIG. 9B. Ifthe tensile load continues, then the tether itself will separate, asshown in FIG. 9C.

[0028]FIG. 10 illustrates the arrangement of the tether and tube 25. Asshown, a loop is formed in the end portion of the tether by means of aferrule 33 threaded on to the bight 34 of the tether and receiving alsothe free end 35 of the tether after that free end has been passed aroundthe sleeve 30. The loop is pulled tight and then the ferrule 33 crimpedto secure the end portion in place. The excess length of the tether ishanked inside the tube 25, as shown at 36. Rubber glands 37 are fittedover the ends of the tube 25 with the tether passing out of thoseglands, the tether being lightly gripped by the glands 37 so as toresist inadvertent withdrawal of the tether, other than when theconnector 18 separates.

[0029] The strength of the tether as well as the material from which itis made should be selected having regard to the load required toseparate the connector 18, at well as the energy stored in the hose 14at the point of separation. However, to ensure the tether will separatebefore further energy builds up in the hose 14, the breaking load of thetether should be very much less than the separation load of theconnector 18, which could be as much as 250 lbf.

1. A safety device for a fluid hose having at one end one part of aseparable connector by means of which the hose may be freed from anotherpipe carrying the other part of the connector when the connector issubjected to a tensile load, which device comprises an elongate tetherhaving one end attached to the hose at or adjacent said one part of theconnector and its other end attached to the pipe at or adjacent theother part of the connector, the tether being arranged to part when theconnector parts have separated under an applied load only once theseparation of the connector parts exceeds a pre-set distance.
 2. Asafety device as claimed in claim 1, wherein the breaking strain of thetether is lower than said load required to separate the connector.
 3. Asafety device as claimed in claim 1 or claim 2, wherein the length ofthe tether is greater than the distance between the attachment pointsthereof respectively to the hose and pipe, the excess length of thetether being contained in packaging disposed alongside the connector. 4.A safety device as claimed in claim 3, wherein the packaging comprises arigid tube, the two end portions of the tether leaving the tuberespectively through the two ends of the tube.
 5. A safety device asclaimed in claim 4, wherein each end of the tube is provided withfriction means to resist the movement of the tether out of the tube. 6.A safety device as claimed in claim 5, wherein the friction meanscomprises a resilient gland through which the tether passes.
 7. A safetydevice as claimed in any of the preceding claims, wherein the tethercomprises a synthetic material cord or strap.
 8. A safety device asclaimed in claim 1, wherein the tether comprises a strop of a syntheticpolymer which undergoes significant extension under a substantiallyconstant tensile load until the strop reaches its breaking point.
 9. Asafety device as claimed in any of the preceding claims, wherein one endportion of the tether is secured to the hose by means of a loop passingaround the hose which loop is formed by the free end of the tether beingsecured to the bight by means of a crimped ferrule.
 10. A safety deviceas claimed in any of claims 1 to 8, wherein the tether is secured to thetwo parts of the coupling so as to be indirectly connected to the hoseand pipe.
 11. A safety device as claimed in claim 10, wherein acomponent of each coupling part is provided with a lug to which the endportion of the tether is secured.
 12. A safety device as claimed inclaim 1, wherein the tether extends internally of the coupling.
 13. Asafety device as claimed in claim 1 and substantially as hereinbeforedescribed with reference to and as illustrated in the accompanyingdrawings.
 14. A liquid-fuel pump having a flexible fuel delivery hoseconnected to a fuel delivery pipe by means of a two part connectorarranged to separate when the tensile load applied to the hose exceeds apre-determined value, whenever the connector is fitted with a safetydevice as claimed in any of the preceding claims.
 15. A liquid-fuel pumphaving a flexible fuel delivery hose connected to a dispensing nozzle bymeans of a two part connector arranged to separate when the tensile loadapplied to the hose exceeds a pre-determined value, whenever theconnector is fitted with a safety device as claimed in any of thepreceding claims.